Saturday, January 12, 2013

Viruses, History of virology, History of virology, Names and Classification of viruses, Isolation Viruses

History of virology

Counting the history of virology should be conducted on February 12, 1892, when D.Y.Yvanovskyy told the Academy of Sciences of the opening of the pathogen "tobacco mosaic." Interest in virology growing with the opening of oncogenic viruses (1911) and bacteriophages, when foundations culturing viruses.
Currently Virology - is one of the most rapidly developing science, where the virus as the most simply organized forms of life allow many fundamental questions of molecular biology and genetic engineering.


Viruses genome
non-cellular life forms that have their own genome, represented or ribonucleic acid (RNA) or deoxyribonucleic (DNA) acids. Viruses containing RNA can be regarded as a separate branch of evolution. Viruses are obligate intracellular parasites of humans, animals, insects, plants, fungi and bacteria. They are deprived beloksyntezyruyuschey, enzymatic and energy systems are not capable of self-reproduction. A prerequisite for this is the synthesis of virus-specific proteins and viral genome of host cells.

Names and Classification of viruses

All viruses exist in two forms: extracellular (virion) and intracellular (virus).
Classification of viruses is based on the type of nucleic acid of interest content in its virion, including strings in it, relative molecular mass, structural features of virus reproduction, etc.Usually viruses are called or as they cause disease, or name where they were selected, or use the names of scientists have identified them, etc.
Names and Classification of viruses
In RNA viruses are pikornavirusy togavirusov, kalitsivirusy, coronavirus, retroviruses bunyavirusam, arenavirusy ortomiksovirusy, paramyxovirus, rabdovyrusov, reovirus. By DNA viruses include parvovirus, papovirusy, adenoviruses, herpesvirus, poksvyrusov, hepadnavirusa.On the morphology of viruses are divided into four groups: spherical, palochkovydnuyu, kuboidalnuyu, spermatozoyidnoyi.
Virion consists of a centrally located nukleoproteyda surrounded by one or two shells.
Interaction "cell - virus" may be politically character and end with the death of infected cells or be in the nature of a stable interaction does not lead to cell death (latent infection).

Cycle of viral replication

Cycle of viral replication
The cycle of viral replication in the lytic interaction consists of the following stages:
1-adsorbirovanie virus to the host cell
2-penetration into the cell and "stripping" of the virus
3-synthesis of viral proteins by biosynthetic systems of the host cell
4-full samoskladannya intracellular virus
5-release of virions subsidiaries in the destruction of cells or by budding.

Chicken embryos-Viruses

Isolation Viruses

Viruses multiply only sensitive to them living cells. Isolation chirusa of pathological material performed on cell cultures. Cell cultures obtained after dispersing the organs and tissues and placed on a flat surface, where they grow as a monolayer.Cytopathic effect of viruses on sensitive cells can be expressed in the formation of multinucleated sintsitiya, rounding cell lysis zone formation in monolayer, the appearance of the infected cells characteristic formations - inclusion bodies visible in the light microscope. If you can not isolate and identify the virus in vitro pathological material injected into susceptible animals, and after the development of the infectious process producing re-infected cell cultures.
Chicken embryos - an ideal model for the cultivation of certain viruses. Naturally susceptible animals in the same vein is now rarely used.
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